To most advertisers, the highest-value ad space is that which is most relevant to their products or services. For instance, a food brand would naturally gravitate to cooking sites.

This mindset is born of print, radio, and television advertising. In other words, it's display-based thinking. There's nothing wrong with it. In fact, it's been proven effective over many years.

There are, however, more effective and accountable ways of delivering video advertising. Let's stick with the food example. The advertiser is a national brand of olive oil that targets moms who like...